1. Field of the Invention
The present invention relates in general to a baby/patient monitor, and in particular to a monitor capable of measuring flux of IR radiation emitted by body of a baby or a disabled patient.
2. Description of Related Art
Baby monitors are well known. A standard baby monitor consists of two physically separate units: a baby unit and a parent unit, each of which can be powered by a battery or an AC current source. The baby unit contains a microphone or other sound detecting device and is placed in a location near a baby. The parent unit contains a speaker and is placed in a location near the baby's guardian. A sound (e.g. a stirring or crying baby) detected by the baby unit is transmitted to the parent unit for output to the guardian to hear and respond to accordingly.
Several versions of this standard model exist. One of them involves a number of light emitting diodes (LEDs), which turn on in series to indicate a level of the sound measured by the microphone. This visual alert is useful when other noises may interfere with the receiver audio output.
In another version of the system the parent unit is capable of sending audible or other information to the baby unit, that provides means for comforting the baby without the need to approach him/her. Such baby monitors with soothing units are described by Fitzgerald, et al., U.S. Pat. No. 6,759,961, Altenhofen; Cynthia L, U.S. Pat. No. 6,043,747.
Some similar devices include enhancements, which allow monitoring other parameters relevant to baby's conditions, such as baby's movements or whether his/her clothes are dry (Xiaowei et al., patent CN2301724U). Some of these parameters may be related to baby's health conditions, such as heart beat and/or respiratory rates, as in cardiac and apnea monitoring system (Holland, et al., U.S. Pat. No. 6,764,451). Another example is a psychological monitor utilizing information obtained through measuring EKG of a baby (Mault, et al., U.S. Pat. No. 6,790,178). An invention documented by Jackson, III in U.S. Pat. No. 6,047,201 is designed to measure level of oxygen in infant's blood.
Pediatricians nowadays consider that an important factor in a very young child's life is ambient temperature and thus it is therefore necessary for the ambient temperature of the child's room to be taken into account, and for the appropriate changes to be made if the temperature rises or falls beyond suitable limits. The invention of Liu Chi Cheung et al., patent EP0983580 addresses this issue.
Other devices permanently display a live image of the baby. The image is acquired by a vide camera, built into the baby unit and is displayed on video screen built into the parent unit. Such a use of a wireless video camera coupled to a TV receiver is described in Ray; Rajarshi, U.S. Pat. No. 6,192,257, Strandwitz, et al., U.S. Pat. No. 6,522,352.
Remote temperature and heat flux measurements based on infrared (IR) technology are used for medical (e.g. I. Kushnir, U.S. Pat. No. 6,508,831), industrial (e.g. M. R. Clark, D. M. McCann and M C. Forde, “Application of IR thermography to the non-destructive testing of concrete and masonry bridges”, NDT & E International, Volume 36, Issue 4, June 2003, Pages 265-275), agricultural (e.g. G. Wright, “IR images to reduce peanut aflatoxin risk”, International CustomWire, Sep. 06, 2004, Item CX200425018851), military (e.g P. L. Martinez et al., “Improved Thermal Analysis of Buried Landmines”, IEEE Transactions on Geoscience & Remote Sensing, September 2004, Vol. 42 Issue 9, p1965) and scientific (e.g. S. Montelpare and R. Ricci, “An experimental method for evaluating the heat transfer coefficient of liquid-cooled short pin fins using IR thermography”, Experimental Thermal and Fluid Science, Volume 28, Issue 8, October 2004, Pages 815-824) applications. The way those proposed technologies are designed makes them inappropriate and/or too expensive for monitoring a baby or a patient at sleep.
Watabe, et al. suggested a way to improve accuracy of temperature/heat flux measurements using 2 IR sensors in U.S. Pat. No. 6,236,046. A similar technique is used in the preferred embodiment of the present invention.
Many parents cover their babies with a blanket or a comforter when the babies sleep. While adults often develop skills to cover/uncover themselves with the blanket in sleep as they feel too cold/warm, babies lack those skills till they reach the age of about 10 years old. Accidental movement of a baby during his/her sleep can therefore lead to his/her inadequate coverage by the blanket. In some cases under such circumstances the baby would wake up and call for a guardian, but this rarely happens instantaneously, and typically the baby would stay asleep while feeling thermal discomfort for some time. That could be a reason for bad dreams, diseases and even fatalities.
In particular, according to medical research, Sudden Infant Death Syndrome (SIDS) is one of the leading causes of post-neonatal mortality in industrialized countries. Substantial proportion of the SIDS deaths could be avoided by providing safe sleeping environment for infants, whereas their overheating is considered as one of the major risk factors (Ponsonby A L, Dwyer T, Cochrane J, New England Journal of Medicine (329(6) 1993; Mathews T J, Menacker F, MacDorman M F, National Vital Statistics Reports 52(2) 2003).
Some baby monitors were invented to specifically address the issue of SIDS. One of such devices is documented by Walton, U.S. Pat. No. 5,864,291. This monitor is attached to baby's torso in order to detect that the baby is no longer breathing and inform the parent of that. Another invention (Gibbon et al. patent WO9819596) alarms the baby's guardian of the fact that the baby's hear is no longer beating.
Additionally, because thermoregulatory neurons are synaptically linked to those regulating respiration, adequate temperature control (especially by infants) maintains normal respiration. Therefore, of particular importance may be the temperature control during sleep of patients with increased risk of asphyxia such as pre-term infants, babies and adults with physical and mental disabilities, as well as elderly patients (Scher M S, Steppe D A, Salerno D G, Beggarly M E, Banks D L, Clinical Neurophysiology 114(1)2003).
The device proposed addressees the issue of informing the guardian about a baby's or patient's thermal discomfort during his/her sleep, while being inexpensive in mass production and easy in use.